![Freescale Semiconductor MCF54455 Reference Manual Download Page 166](http://html1.mh-extra.com/html/freescale-semiconductor/mcf54455/mcf54455_reference-manual_2330541166.webp)
Cache
Freescale Semiconductor
6-21
movec
d0,cacr
;in the CACR
rts
6.4.7
Cache Operation Summary
This section gives operational details for the cache and presents instruction and data cache-line state
diagrams.
6.4.7.1
Instruction Cache State Transitions
Because the instruction cache does not support writes, it supports fewer operations than the data cache. As
shows, an instruction cache line can be in one of two states: valid or invalid. Modified state is
not supported. Transitions are labeled with a capital letter (indicating the previous state) and a number
(indicating the specific case listed in
). These numbers correspond to the equivalent operations
on data caches as described in
Section 6.4.7.2, “Data Cache-State Transitions
Figure 6-10. Instruction Cache Line State Diagram
describes the instruction cache-state transitions shown in
.
Table 6-5. Instruction Cache Line State Transitions
Access
Current State
Invalid (V = 0)
Valid (V = 1)
Read miss
II1 Read line from memory and update cache;
supply data to processor;
go to valid state.
IV1 Read new line from memory and update cache;
supply data to processor; stay in valid state.
Read hit
II2 Not possible
IV2 Supply data to processor;
stay in valid state.
Write miss
II3 Not possible
IV3 Not possible
Write hit
II4 Not possible
IV4 Not possible
Cache
invalidate
II5 No action;
stay in invalid state.
IV5 No action;
go to invalid state.
Cache
push
II6
II7
No action;
stay in invalid state.
IV6 No action;
go to invalid state.
IV7 No action;
stay in valid state.
Valid
V = 1
II5—ICINVA
II6—CPUSHL and IDPI
II7—CPUSHL and IDPI
IV1—CPU read miss
IV2—CPU read hit
IV7—CPUSHL and IDPI
IV5—ICINVA
IV6—CPUSHL and IDPI
Invalid
V = 0
II1—CPU read miss
Summary of Contents for MCF54455
Page 33: ...xxviii Freescale Semiconductor ...
Page 67: ...Freescale Semiconductor 1 ...
Page 125: ...Freescale Semiconductor 1 ...
Page 145: ...Enhanced Multiply Accumulate Unit EMAC 5 21 Freescale Semiconductor ...
Page 173: ...Cache 6 28 Freescale Semiconductor ...
Page 179: ...Static RAM SRAM 7 6 Freescale Semiconductor ...
Page 207: ...Power Management 9 16 Freescale Semiconductor ...
Page 323: ...Reset Controller Module 13 8 Freescale Semiconductor ...
Page 389: ...Pin Multiplexing and Control 16 44 Freescale Semiconductor ...
Page 575: ...PCI Bus Controller 22 58 Freescale Semiconductor ...
Page 600: ...Advanced Technology Attachment ATA Freescale Semiconductor 23 25 ...
Page 601: ...Freescale Semiconductor 1 ...
Page 842: ...I2 C Interface Freescale Semiconductor 33 16 ...
Page 843: ...Freescale Semiconductor 1 ...
Page 921: ...Revision History A 6 Freescale Semiconductor ...